KLF4 and brain ischemia: We found that in response to cerebral ischemia, the expressions of C3 as well as KLF4 were both induced in GFAP positive astrocytes in the ischemic hemisphere over the 14-day time-course, but their distribution patterns were different: where the high levels of KLF4 were expressed, there were relatively low levels of C3, and vice versa.